Safety-valve



R. CORNELIUS Steam Safety Valve.

Patented June 17, 1856.

R. CORNELIUS, OF PHILADELPHIA, PENNSYLVANIA.

SAFETY-VALVE.

Specification of Letters Patent No. 15,120, dated June 17, 1856.

To all whom it may concern:

Be it known that I, ROBERT CORNELIUS, of the city of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Safety-Valves; and I do hereby declare the following to be a full and.

exact description of th same, reference being had to the annexed drawings, making a part of this specification, in which Figure 1, is av vertical section of the safety valve when closed, and Fig. 2, is a vertical View of the same when open.

The nature of my improvement consists in so constructing and arranging the lever and weight of the ordinary safety valve that whenever the valve opens and blows off steam the lever of the safety valve shall be so supported that the intervention of the engineer shall be necessary to readjust the weight and valve in its former position.

The arrangement of the ordinary lever and weight of the safety valve is such that the weight is adjusted to a certain point, and when the steam within the boiler reaches a pressure above that for which the safety valve has been adjusted, the valve opens slightly, and the steam begins to issue around it. As soon as a small portion of the steam has thus escaped and relieved the boiler, the

valve descends, checks the steam, and restores the pressure on the boiler. The steam then again increases in pressure, raises the valve slightly, and is again relieved slightly, the valve falls, and so on. A usual practice for engineers is to go and increase the weight on the safety valve in order to prevent the disagreeable noise incident to the escaping of steam at intervals by reason of the oscillation in the manner above mentioned. Thus he increases the pressure on the boiler, and the consequent danger. The true object of a safety valve is that it should open as soon as the steam reaches the highest point fixed and should present as large an aperture of escape as possible, and that it should remain open until the steam is sensibly and materially reduced in pressure. I think that I have attained this advantageous result by my arrangement of safety valve.

A, Figs. 1 and 2, is an ordinary puppet valve fitting on the top of the pipe B, passing to the boiler.

J, K, L, M, is a stationary frame supporting the valve lever, and is attached permanently to the upper extremity of the pipe B, or otherwise as may be convenient.

The rod C, is attached to the puppet valve A at its lower extremity, and to the lever D, E, at its upper extremity. The lever D, E, turns upon E, as a fulcrum. At its outer extremity D, is placed a vertical rod D, F, with a small projection D, G, attached to it so as to form a bent lever at D. The bent lever F, D, G, turns on D, as a pivot or fulcrum. At G, is a small piece G, H, attached working upon G, as a fulcrum, and this piece is also attached to the fixed frame at H, by another pivot. The elfect of this combination of the bent lever or rod F, D, G, turning on D, in connection with the piece D. H, turning at D, and H, is to cause the joint D, G, H, to act as a toggle joint operated upon by the weight V. The arrangement of these levers, joints, and the weight V, is as follows: Ordinarily th rod F, D, stands upright with the weight W, at its upper extremity, and the valve A, is kept in its seat by the weight W, acting vertically on the extremity of the lever D, E.

WVhen the pressure of steam in the boiler exceeds the resistance produced by the weight W, when in the position just named, the valve A, is forced up; this elevates the point D. The raising of the point D, by reason of the connection of D, G, and G, H, causes the weight to be thrown forward slightly from the perpendicular; then the weight W, by its gravity continues to fall until the jointed pieces D, G, and G, H, are in a straight line, as shown in Fig. 2. The pieces D, G, G, H, then rigidly restrain both the upward and downward movement of the lever D; neither can the extremity of the lever D, E, return to its former position until the steam has been sufficiently reduced in pressure, and until, moreover, the engineer comes and elevates the weight W, and rod F, D, to its former vertical position.

It will thus be seen that as soon as the steam in the boiler reaches the limit of pressure fixed for it, and raises the valve A, from its seat in the slightest degree, immediately the equilibrium of the weight W, on the vertical rod F, D, is destroyed, and the weight WV, falls forward, raises up D, and in consequence also raises up A, to its highest point thus instantly affording a large and free issue of escape for the steam, and moreover this opening at A, is by the action of I the toggle joint at D, G, H, kept open, so as to preserve a constant and free aperture of escape until the pressure of the steam in the boiler has been sensibly relieved, and until the engineer comes and restores the weight and rod F, D, to its former upright position. If the engineer should attempt to restore the weight WV, and rod F, D, to their upright position before the steam had been properly reduced in pressure, the tube A, and the point D, would soon rise slightly, and the weight W, would as before fall, offering again a large passage of escape. The engineer would soon perceive that his only plan was to permit the steam to escape, or lower his fires until the proper pressure was attained.

The great advantage of my improvement is that as soon as the point fixed as the limit of pressure is attained, there is instantly a large aperture of escape opened which opening is also preserved of its full size until the steam is properly reduced in pressure, and until it is again adjusted in full operation as a safeguard against any subsequent un due elevation of pressure.

Attachedto Fig. 1 is a piece marked N, R, which represents an ordinary steam whistle through which the steam escapes, and gives a distinct alarm. This may be very useful in counting houses or offices situated near boilers as a tell tale or indicator to the proprietors. In other cases I would leave the opening for the escape of steam either laterally through a tube, as at S, Fig. 2, or around the upper part of an ordinary single seated valve.

Instead of attaching the lower end of the vertical weight rod D, F, by a toggle joint D, G, H, the rod F, D, might be left to work on D, so that when D, was raised the weight IN would be thrown forward and fall over until caught by some rest or projection N.

-The diminished leverage of the Weight W,

purpose substantially as hereinbefore described.

ROBERT CORNELIUS. Witnesses:

J. H. B. JENKINS, G. GUIDEL. 

